ot_entropy_src: unify implementations from EarlGrey and Darjeeling

.gitlab-ci.d/opentitan/ot-smoke.yml

@@ -11,5 +11,5 @@ smoke-tests-ot:
     - timeout -s KILL 4 build/qemu-system-riscv32 -M ot-earlgrey,no_epmp_cfg=true -nographic
         -object ot-rom_img,id=rom,file=build/exit_eg.bin -d in_asm,int
     - timeout -s KILL 4 build/qemu-system-riscv32 -M ot-darjeeling,no_epmp_cfg=true
-        -object ot-rom_img,id=rom,file=build/exit_eg.bin -d in_asm,int
+        -object ot-rom_img,id=rom,file=build/exit_dj.bin -d in_asm,int
          -nographic -global ot-ibex_wrapper.lc-ignore=on

hw/opentitan/Kconfig

@@ -16,13 +16,14 @@ config OT_AON_TIMER
 
 config OT_AST_DJ
     select IBEX_CLOCK_SRC
-    select OT_RANDOM_SRC
     select OT_CLOCK_CTRL
+    select OT_NOISE_SRC
     bool
 
 config OT_AST_EG
     select IBEX_CLOCK_SRC
     select OT_CLOCK_CTRL
+    select OT_NOISE_SRC
     bool
 
 config OT_CLKMGR
@@ -52,12 +53,8 @@ config OT_DMA
 config OT_EDN
     bool
 
-config OT_ENTROPY_SRC_EG
-    select OT_RANDOM_SRC
-    bool
-
-config OT_ENTROPY_SRC_DJ
-    select OT_RANDOM_SRC
+config OT_ENTROPY_SRC
+    select OT_NOISE_SRC
     bool
 
 config OT_FLASH
@@ -112,6 +109,9 @@ config OT_MBX
     select OT_COMMON
     bool
 
+config OT_NOISE_SRC
+    bool
+
 config OT_OTBN
     select OT_KEY_SINK
     select OT_BIGNUMBER
@@ -158,9 +158,6 @@ config OT_PWRMGR
     select OT_CLOCK_CTRL
     bool
 
-config OT_RANDOM_SRC
-    bool
-
 config OT_ROM_CTRL
     bool
     select OT_COMMON

hw/opentitan/meson.build

@@ -18,8 +18,7 @@ system_ss.add(when: 'CONFIG_OT_DEV_PROXY', if_true: files('ot_dev_proxy.c'))
 system_ss.add(when: 'CONFIG_OT_DM_TL', if_true: files('ot_dm_tl.c'))
 system_ss.add(when: 'CONFIG_OT_DMA', if_true: [files('ot_dma.c'), libtomcrypt_dep])
 system_ss.add(when: 'CONFIG_OT_EDN', if_true: files('ot_edn.c'))
-system_ss.add(when: 'CONFIG_OT_ENTROPY_SRC_DJ', if_true: [files('ot_entropy_src_dj.c'), libtomcrypt_dep])
-system_ss.add(when: 'CONFIG_OT_ENTROPY_SRC_EG', if_true: [files('ot_entropy_src_eg.c'), libtomcrypt_dep])
+system_ss.add(when: 'CONFIG_OT_ENTROPY_SRC', if_true: [files('ot_entropy_src.c'), libtomcrypt_dep])
 system_ss.add(when: 'CONFIG_OT_FLASH', if_true: files('ot_flash.c'))
 system_ss.add(when: 'CONFIG_OT_GPIO_DJ', if_true: files('ot_gpio_dj.c'))
 system_ss.add(when: 'CONFIG_OT_GPIO_EG', if_true: files('ot_gpio_eg.c'))
@@ -33,6 +32,7 @@ system_ss.add(when: 'CONFIG_OT_KEYMGR_DPE', if_true: files('ot_keymgr_dpe.c'))
 system_ss.add(when: 'CONFIG_OT_KMAC', if_true: [files('ot_kmac.c'), libtomcrypt_dep])
 system_ss.add(when: 'CONFIG_OT_LC_CTRL', if_true: files('ot_lc_ctrl.c'))
 system_ss.add(when: 'CONFIG_OT_MBX', if_true: files('ot_mbx.c'))
+system_ss.add(when: 'CONFIG_OT_NOISE_SRC', if_true: files('ot_noise_src.c'))
 system_ss.add(when: 'CONFIG_OT_OTBN', if_true: files('ot_otbn.c'))
 system_ss.add(when: 'CONFIG_OT_OTP', if_true: files('ot_otp.c'))
 system_ss.add(when: 'CONFIG_OT_OTP_BE_IF', if_true: files('ot_otp_be_if.c'))
@@ -46,7 +46,6 @@ system_ss.add(when: 'CONFIG_OT_PRESENT', if_true: files('ot_present.c'))
 system_ss.add(when: 'CONFIG_OT_PRINCE', if_true: files('ot_prince.c'))
 system_ss.add(when: 'CONFIG_OT_PRNG', if_true: files('ot_prng.c'))
 system_ss.add(when: 'CONFIG_OT_PWRMGR', if_true: files('ot_pwrmgr.c'))
-system_ss.add(when: 'CONFIG_OT_RANDOM_SRC', if_true: files('ot_random_src.c'))
 system_ss.add(when: 'CONFIG_OT_ROM_CTRL', if_true: files('ot_rom_ctrl.c', 'ot_rom_ctrl_img.c'))
 system_ss.add(when: 'CONFIG_OT_RSTMGR', if_true: files('ot_rstmgr.c'))
 system_ss.add(when: 'CONFIG_OT_SENSOR_EG', if_true: files('ot_sensor_eg.c'))

hw/opentitan/ot_ast_dj.c

@@ -37,7 +37,7 @@
 #include "hw/opentitan/ot_ast_dj.h"
 #include "hw/opentitan/ot_clock_ctrl.h"
 #include "hw/opentitan/ot_common.h"
-#include "hw/opentitan/ot_random_src.h"
+#include "hw/opentitan/ot_noise_src.h"
 #include "hw/qdev-properties.h"
 #include "hw/registerfields.h"
 #include "hw/riscv/ibex_clock_src.h"
@@ -134,11 +134,8 @@ static const char REGB_NAMES[REGSB_COUNT][6U] = {
 };
 #undef REG_NAME_ENTRY
 
-typedef struct {
-    QEMUTimer *timer;
-    uint64_t *buffer;
-    bool avail;
-} OtASTDjRandom;
+/* @todo check with HW what is the best default value */
+#define OT_AST_DJ_NOISE_BITRATE_DEFAULT 1000000u /* 1 MHz */
 
 typedef struct {
     char *name;
@@ -154,7 +151,6 @@ struct OtASTDjState {
     SysBusDevice parent_obj;
 
     MemoryRegion mmio;
-    OtASTDjRandom random;
 
     GList *clocks; /* OtASTDjClock */
 
@@ -163,63 +159,14 @@ struct OtASTDjState {
 
     char *cfg_topclocks;
     char *cfg_aonclocks;
+    uint32_t noise_bitrate;
 };
 
 struct OtASTDjClass {
     SysBusDeviceClass parent_class;
     ResettablePhases parent_phases;
 };
 
-#define OT_AST_DJ_RANDOM_FILL_RATE_NS 1000000ull /* arbitrary: 1 ms */
-
-/* -------------------------------------------------------------------------- */
-/* Private implementation */
-/* -------------------------------------------------------------------------- */
-
-static int ot_ast_dj_get_random(
-    OtRandomSrcIf *dev, uint64_t random[OT_RANDOM_SRC_DWORD_COUNT], bool *fips)
-{
-    OtASTDjState *s = OT_AST_DJ(dev);
-    OtASTDjRandom *rnd = &s->random;
-
-    if (!rnd->avail) {
-        /* not ready */
-        trace_ot_ast_no_entropy(0);
-        int wait_ns;
-        if (timer_pending(s->random.timer)) {
-            wait_ns = 1;
-        } else {
-            /* computed delay fits into a 31-bit value */
-            wait_ns = (int)(timer_expire_time_ns(s->random.timer) -
-                            qemu_clock_get_ns(OT_VIRTUAL_CLOCK));
-        }
-        return wait_ns;
-    }
-
-    memcpy(random, rnd->buffer, OT_RANDOM_SRC_DWORD_COUNT * sizeof(uint64_t));
-    rnd->avail = false;
-
-    /* note: fips compliancy is only simulated here for now */
-    *fips = true;
-
-    uint64_t now = qemu_clock_get_ns(OT_VIRTUAL_CLOCK);
-    timer_mod(rnd->timer, (int64_t)(now + OT_AST_DJ_RANDOM_FILL_RATE_NS));
-
-    return 0;
-}
-
-static void ot_ast_dj_random_scheduler(void *opaque)
-{
-    OtASTDjState *s = opaque;
-    OtASTDjRandom *rnd = &s->random;
-
-    qemu_guest_getrandom_nofail(rnd->buffer,
-                                OT_RANDOM_SRC_DWORD_COUNT * sizeof(uint64_t));
-
-    rnd->avail = true;
-}
-
-
 static const char *CFGSEP = ",";
 
 static gint ot_ast_dj_match_clock_by_name(gconstpointer a, gconstpointer b)
@@ -309,6 +256,21 @@ static void ot_ast_dj_clock_ext_freq_select(OtClockCtrlIf *dev, bool enable)
     qemu_log_mask(LOG_UNIMP, "%s: not implemented: %u\n", __func__, enable);
 }
 
+static unsigned ot_ast_dj_get_fill_rate(OtNoiseSrcIf *dev)
+{
+    OtASTDjState *s = OT_AST_DJ(dev);
+
+    return s->noise_bitrate / 8u; /* bit to byte */
+}
+
+static void ot_ast_dj_get_noise(OtNoiseSrcIf *dev, uint8_t *buffer,
+                                size_t length)
+{
+    (void)dev;
+
+    qemu_guest_getrandom_nofail((void *)buffer, length);
+}
+
 static void ot_ast_dj_parse_clocks(OtASTDjState *s, Error **errp)
 {
     if (!s->cfg_topclocks) {
@@ -510,6 +472,8 @@ static void ot_ast_dj_regs_write(void *opaque, hwaddr addr, uint64_t val64,
 static Property ot_ast_dj_properties[] = {
     DEFINE_PROP_STRING("topclocks", OtASTDjState, cfg_topclocks),
     DEFINE_PROP_STRING("aonclocks", OtASTDjState, cfg_aonclocks),
+    DEFINE_PROP_UINT32("noise-bitrate", OtASTDjState, noise_bitrate,
+                       OT_AST_DJ_NOISE_BITRATE_DEFAULT),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -525,16 +489,11 @@ static void ot_ast_dj_reset_enter(Object *obj, ResetType type)
 {
     OtASTDjClass *c = OT_AST_DJ_GET_CLASS(obj);
     OtASTDjState *s = OT_AST_DJ(obj);
-    OtASTDjRandom *rnd = &s->random;
 
     if (c->parent_phases.enter) {
         c->parent_phases.enter(obj, type);
     }
 
-    timer_del(rnd->timer);
-    memset(rnd->buffer, 0, OT_RANDOM_SRC_DWORD_COUNT * sizeof(uint64_t));
-    rnd->avail = false;
-
     memset(s->regsa, 0, REGSA_SIZE);
     memset(s->regsb, 0, REGSB_SIZE);
 
@@ -584,15 +543,11 @@ static void ot_ast_dj_reset_exit(Object *obj, ResetType type)
 {
     OtASTDjClass *c = OT_AST_DJ_GET_CLASS(obj);
     OtASTDjState *s = OT_AST_DJ(obj);
-    OtASTDjRandom *rnd = &s->random;
 
     if (c->parent_phases.exit) {
         c->parent_phases.exit(obj, type);
     }
 
-    uint64_t now = qemu_clock_get_ns(OT_VIRTUAL_CLOCK);
-    timer_mod(rnd->timer, (int64_t)(now + OT_AST_DJ_RANDOM_FILL_RATE_NS));
-
     g_list_foreach(s->clocks, ot_ast_dj_update_clock, s);
 }
 
@@ -614,11 +569,6 @@ static void ot_ast_dj_init(Object *obj)
 
     s->regsa = g_new0(uint32_t, REGSA_COUNT);
     s->regsb = g_new0(uint32_t, REGSB_COUNT);
-
-    OtASTDjRandom *rnd = &s->random;
-
-    rnd->timer = timer_new_ns(OT_VIRTUAL_CLOCK, &ot_ast_dj_random_scheduler, s);
-    rnd->buffer = g_new0(uint64_t, OT_RANDOM_SRC_DWORD_COUNT);
 }
 
 static void ot_ast_dj_class_init(ObjectClass *klass, void *data)
@@ -636,15 +586,16 @@ static void ot_ast_dj_class_init(ObjectClass *klass, void *data)
                                        &ot_ast_dj_reset_exit,
                                        &ac->parent_phases);
 
-    OtRandomSrcIfClass *rdc = OT_RANDOM_SRC_IF_CLASS(klass);
-    rdc->get_random_values = &ot_ast_dj_get_random;
-
     IbexClockSrcIfClass *ic = IBEX_CLOCK_SRC_IF_CLASS(klass);
     ic->get_clock_source = &ot_ast_dj_get_clock_source;
 
     OtClockCtrlIfClass *cc = OT_CLOCK_CTRL_IF_CLASS(klass);
     cc->clock_enable = &ot_ast_dj_clock_enable;
     cc->clock_ext_freq_select = &ot_ast_dj_clock_ext_freq_select;
+
+    OtNoiseSrcIfClass *nc = OT_NOISE_SRC_IF_CLASS(klass);
+    nc->get_fill_rate = &ot_ast_dj_get_fill_rate;
+    nc->get_noise = &ot_ast_dj_get_noise;
 }
 
 static const TypeInfo ot_ast_dj_info = {
@@ -656,9 +607,9 @@ static const TypeInfo ot_ast_dj_info = {
     .class_init = &ot_ast_dj_class_init,
     .interfaces =
         (InterfaceInfo[]){
-            { TYPE_OT_RANDOM_SRC_IF },
             { TYPE_IBEX_CLOCK_SRC_IF },
             { TYPE_OT_CLOCK_CTRL_IF },
+            { TYPE_OT_NOISE_SRC_IF },
             {},
         },
 };

hw/opentitan/ot_ast_eg.c

@@ -36,6 +36,7 @@
 #include "hw/opentitan/ot_ast_eg.h"
 #include "hw/opentitan/ot_clock_ctrl.h"
 #include "hw/opentitan/ot_common.h"
+#include "hw/opentitan/ot_noise_src.h"
 #include "hw/qdev-properties.h"
 #include "hw/registerfields.h"
 #include "hw/riscv/ibex_clock_src.h"
@@ -132,6 +133,8 @@ static const char REGB_NAMES[REGSB_COUNT][6U] = {
 };
 #undef REG_NAME_ENTRY
 
+#define OT_AST_EG_NOISE_4BIT_RATE 50000u /* 50 kHz */
+
 typedef struct {
     char *name;
     unsigned frequency;
@@ -161,16 +164,6 @@ struct OtASTEgClass {
     ResettablePhases parent_phases;
 };
 
-/* -------------------------------------------------------------------------- */
-/* Public API */
-/* -------------------------------------------------------------------------- */
-
-void ot_ast_eg_getrandom(void *buf, size_t len)
-{
-    qemu_guest_getrandom_nofail(buf, len);
-}
-
-
 static const char *CFGSEP = ",";
 
 static gint ot_ast_eg_match_clock_by_name(gconstpointer a, gconstpointer b)
@@ -260,6 +253,21 @@ static void ot_ast_eg_clock_ext_freq_select(OtClockCtrlIf *dev, bool enable)
     qemu_log_mask(LOG_UNIMP, "%s: not implemented: %u\n", __func__, enable);
 }
 
+static unsigned ot_ast_eg_get_fill_rate(OtNoiseSrcIf *dev)
+{
+    (void)dev;
+
+    return OT_AST_EG_NOISE_4BIT_RATE / 2u; /* 4 bits to byte */
+}
+
+static void ot_ast_eg_get_noise(OtNoiseSrcIf *dev, uint8_t *buffer,
+                                size_t length)
+{
+    (void)dev;
+
+    qemu_guest_getrandom_nofail((void *)buffer, length);
+}
+
 static void ot_ast_eg_parse_clocks(OtASTEgState *s, Error **errp)
 {
     if (!s->cfg_topclocks) {
@@ -580,6 +588,10 @@ static void ot_ast_eg_class_init(ObjectClass *klass, void *data)
     OtClockCtrlIfClass *cc = OT_CLOCK_CTRL_IF_CLASS(klass);
     cc->clock_enable = &ot_ast_eg_clock_enable;
     cc->clock_ext_freq_select = &ot_ast_eg_clock_ext_freq_select;
+
+    OtNoiseSrcIfClass *nc = OT_NOISE_SRC_IF_CLASS(klass);
+    nc->get_fill_rate = &ot_ast_eg_get_fill_rate;
+    nc->get_noise = &ot_ast_eg_get_noise;
 }
 
 static const TypeInfo ot_ast_eg_info = {
@@ -593,6 +605,7 @@ static const TypeInfo ot_ast_eg_info = {
         (InterfaceInfo[]){
             { TYPE_IBEX_CLOCK_SRC_IF },
             { TYPE_OT_CLOCK_CTRL_IF },
+            { TYPE_OT_NOISE_SRC_IF },
             {},
         },
 };